Apparatus for the acoustic treatment of liquids



Dec. 25, 1962 w. K. FORTMAN ,0

APPARATUS FOR THE ACOUSTIC TREATMENT OF LIQUIDS Filed March 5, 1962 INVENTOR WILLIAM K. FORTMAN BY imwl H. K' a ATTORNEY United States Patent 3,070,313 APPARATUS FOR THE ACOUSTIC TREATMENT OF LIQUIDS William K. Fortman, Syosset, N.Y., assignor to Astrosonics, Inc., Syosset, N.Y. Filed Mar. 5, 1962, Ser. No. 177,395 7 Claims. (Cl. 239102) This invention relates to an improved apparatus for the acoustic treatment of liquids. The apparatus may, by way of example and without intent to be limiting, be employed for atomization, spray-drying, agglomeration of airborne contaminants, and/or deposition of liquids by subjection of the liquid to sonic energy.

Briefly stated, the invention employs an acoustic generator of the Hartmann type, such as disclosed, for example, in US. Patent No. 2,519,619 to Yellott and Savory for Acoustic Generator. The liquid to be treated is dispensed through an annular premixing chamber which uniformly distributes the liquid through jet orifices into the sonic field produced by the acoustic generator.

It is a feature of this invention to provide a sonic energy reflector so located as to prevent fluids from contaminating the resonator.

Still another feature of this invention is to provide a sonic energy spray nozzle requiring relatively low gas and liquid operating pressures.

A further feature of this invention is to provide an improved, sonic energy liquid treating apparatus.

A particular feature of this invention is to provide a spray nozzle of the type described wherein the liquid inlet orifices may be positioned at an optimum distance from the resonator.

These and still other objects and advantages of the invention will, in part, be pointed out with particularity and will, in part, become obvious as the following description proceeds taken in conjunction with the accompanying drawing.

In the drawing:

FIG. 1 is a perspective showing of the spray apparatus of this invention.

FIG. 2 is a vertical section taken through the center of the apparatus.

FIG. 3 is a section taken along line 3-3 of FIG. 2.

Referring now to FIG. 1 of the drawing, there is shown a plane wave spray nozzle designated generally by the reference numeral 10. A standard Ms pipe fitting 11 is provided for coupling to a liquid supply and a standard pipe fitting 12 is provided for coupling to a gas supply. The gas supply may be steam, air, inert gases such as nitrogen, highly reactive gases such as oxygen and chlorine, solvent gases such as carbon tetrachloride vapor or other compressible fluid.

Gas passing through nozzle 14 is compressed in resonator cavity or well 16, as explained in the aforementioned US. Patent No. 2,619,619. Liquid is simultaneously sprayed into the sonic field for treatment. It has been found that some liquids will dry faster into particles or beads after exposure to the sonic field. Many gelatines and waxes will fall to a collection basin in dry form after spraying into a sonic field at room temperature. Other materials need to be sprayed into a heated atmosphere for drying to occur.

The internal construction of the apparatus is shown in FIGS. 2 and 3. While a 300 series stainless steel in generally suitable, for special applications cermets, ceramics and other suitable materials may be employed. The body 20 is conveniently machined of two mating pieces 21 and 22, respectively, which are force fit to form a unitary member. Force fit within portion 21, there is provided a spider 23. Fitting within a central bore formed in the 3,070,313 Patented Dec. 2 5, 1962 spider there is provided a supporting stem 24 which may be moved axially by means of adjusting screw 25. When a suitable axial position is attained, as indicated by a desired spray pattern, a hole is drilled into supporting stem 24 and screw 25 and a locking pin 26 inserted to lock the spider, supporting stem, and screw, in position. The portion of the hole extending through members 21 and 23 may be drilled in advance. Resonator cup 30 is pinned to the end of supporting stem 24 by pin 32. It will be noted that member 22 is provided with a conical bore forming a restricted throat 34 which again tapers outwardly in a downward direction at about a 15 angle to form nozzle 14. The throat dimension should be deslgned to provide an increase of air velocity to about Mach 1.0. The subsequent increase in diameter to form expanded nozzle 14 results in achieving of a velocity of about Mach 1.5.

The mode of operation of the acoustic generator is well described in the literature as, for example, in the aforementioned US. Patent No. 2,519,619, and accordingly need not be described herein.

The liquid to be treated is introduced through fitting 11 and passes through tube 35 into an annular mixing chamber 38.

The body member 39 enclosing chamber 38 may readily be formed by ordinary machining techniques. The body member is composed of two major sections. The first is an annular member 40 provided with an open annular recess. Member 40 threads onto body portion 22 of the acoustic generator. The other section comprises an annular cover member 42 which threads into body 40 to define the enclosed annular chamber 38. O-rings 44 and 46 provide a liquid tight seal between members 40 and 42. Liquid is dispensed through orifices 18 extending into annular chamber 38. The method of assembling the annular chamber to the acoustic generator is advantageous as it permits employment of one acoustic generator with a wide range of annular chamber assemblies having a different distribution arrangement or orifice size. The chamber should be sufficiently large as to permit free circulation and uniform distribution of the liquid to all orifices. By way of example, a chamber A x has been found to be suitable. A spacing between the bottom of the annular chamber (at the orifice) to the midpoint between the end of the nozzle 14 and the resonator 30 of one wavelength at the frequency at which the resonator is operating has been found suitable. Generally an operating frequency in the range of 7000 to 9500 c.p.s. is preferred.

Thus as the sonic energy field is generated in the well 16, it is directed upwardly toward the radial face 41 of member 39. The radial face serves to beam the sonic energy field downwardly and outwardly so that the energy is not randomly dissipated. At the same time the liquid is injected into the field.

The following experimental results were obtained employing a device as described having 8 orifices, each 0.40" in diameter.

Operational range (air) ..p.s.i.g l560 Volumetric flow range (air) s.c.f.m 14-33 Frequency range c.p.s 7000-9500 Flow conditions:

006 g.p.m 0.5 lb./min. 20-40 micron droplets 1.92 g.p.m 16.0 lb./min. 300-400 micron droplets.

an acoustic generator having an orificed nozzle for producing a fluid jet;

an oscillator having a well in spaced opposed relationship to said nozzle orifice;

a member surrounding said acoustic generator, said member defining an annular liquid-receiving chamber and having a plurality of holes communicating from the chamber to an exterior portion of said member above said nozzle orifice; and

conduit means for introducing liquid into said chamber.

2. The apparatus of claim 1 wherein said member is detachable from said acoustic generator.

3. The apparatus of claim 1 provided with a throat portion of lesser diameter than said nozzle immediately upstream from said nozzle.

4. The apparatus of claim 3 in combination with a compressible fluid source under sufiicient pressure to produce a fluid jet having a velocity of at least Mach 1 at said throat and in excess thereof at said nozzle.

5. The apparatus of claim 3 in combination with a source of a compressible fluid at sufiicient pressure to produce a fluid jet at said nozzle in excess of Mach 1.

6. An apparatus for treating liquids by sonic energy comprising:

an acoustic generator having an orificed nozzle for producing a fiuid jet;

a rod extending axially into said orifice;

an oscillator, having a well in spaced opposed relationship to said nozzle orifice supported by said rod;

means to axially move said rod;

a member surrounding said acoustic generator, said member defining an annular liquid-receiving chamber and having a plurality of holes communicating from the chamber to a portion of said member above said nozzle orifice; and

conduit means for introducing liquid into said chamber.

4 7. An apparatus for treating liquids by sonic energy comprising:

an acoustic generator for producing a sonic energy field having an orificed nozzle for producing a fluid jet; a rod extending axially into said orifice;

an oscillator, having a well in spaced opposed relationship to said nozzle orifice supported by said rod and for producing a sonic field directed towards said nozzle;

means to axially move said rod;

a member surrounding said acoustic generator and having a radial face positioned in the path of said field upstream, with reference to the fluid jet from this nozzle, said member defining an annular liquidreceiving chamber having a plurality of holes communicating therefrom to said radial face and arranged to dispense liquid into the resultant sonic field; and

conduit means for introducing liquid into said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 1,939,302 Heaney Dec. 12, 1933 2,481,620 Rosenthal Sept. 13, 1949 2,519,619 Yellott et a1 Aug. 22, 1950 2,908,443 Fruengel Oct. 13, 1959 2,944,029 Jones et a1. "July 5, 1960 OTHER REFERENCES 

